msiexec.exe is a legitimate process, which is located in C:\Windows\System32. This file can also be called a part of a Windows Installer, which is important for a successful installation of a new software. Typically, msiexec.exe runs in the background of the system and helps users to install programs that require Windows Installer package files for their installation. It is a harmless process, so you should never terminate it.
If you noticed that msiexec.exe is located in other, not in C:\Windows\System32 folder, it means that your computer is infected by a malicious process that uses this process to hide itself from your antivirus. Any malware can be named anything, so msiexec.exe is also not an exception. According to security experts, this file name has been used by trojan horse and other dangerous programs that helped scammers steal personal people's information, infect their computers with malware and initiate similar dangerous activities. If you think that your msiexec.exe version might be malicious, you should waste no time and check its trustworthiness with RegCure Pro or Reimage.